plan seems to be ok vastu wise. (assuming north -south axis is diagonal and not aligned to the axis of the house)

regarding son's bedroom 1 - try making the washroom more square towards the left exterior wall and the box room in front of it. Best to keep wet areas together, i.e. wc, shower and tub in one zone and dry area i.e. the basin in one zone. Also you could change the orientation of the bed as there is no privacy in the current layout. Maybe same as guest room's bed orientation. Another option would be to to re orient the door.

the dining area also should have some window opening.

The master bedroom, in spite of being of good size, has hardly any wardrobe space. The space before the 2 pillars could be used for wardrobes with some rework on the walls and door alignment.

I feel the whole plan needs some re working to take out the best use of the space.

You can send us the autocad plan and we can help you rethink the layout along with interior design help.